On Tuesday, the Telangana government found an active P2 strain of Vaccine Derived Polio Virus (VDPV) in a sample collected from a drain. The state government sounded a global emergency and is administering polio vaccines to about 3 lakh children in Hyderabad and Ranga Reddy district as a precautionary step.
While Indiaâ€™s drive to eradicate polio has been internationally appreciated, cases of Vaccine Derived Polio Virus (VDPV) have surfaced in India time and again, pointing towards an implementation loophole.
Previous cases of VDPV in India
While India has been termed polio-free since 2011 (the last report of WPV was in 2011), this does not count cases of VDPVs, whichsignify continually low levels of immunity to the virus in a community. These occur when routine immunization (RI) is not done regularly.
For instance, in 2009, the virus was detected in East Champaran, Bihar in an 18-month-old boy. According to the Indian Pediatrics report cited above, it appeared that the boy had received several doses of pulse polio but not of RI, making him susceptible to the virus.
In the same year, two cases of VDPV were detected in Assamâ€™s Dibrugarh district. This was two months after a 4.5-year-old child wasdetected with a vaccine-derived strain. Massive immunization drives followed.
In November last year, an infant was detected with a polio strain which was also a case of VDPV, in Delhi. Before, this, another case was reported in Maharashtra in 2013.
Although India even received a certificate from the WHO in 2014, the status of polio-free comes with caveats. According to a report in The Hindu, between January 2014 and March 2015, India reported four cases of VDPV from four states. Further, while cases of acute flaccid paralysis (AFP) due to polio have decreases, cases of non-polio acute flaccid paralysis (NPAFP) have been on the rise. The latter is clinically similar to polio except that it is not caused from the polio virus.
Between 2011 and 2014, India has seen about 50,000 cases of NPAFP, which, the report says, is directly related to administration of the OPV. According to WHO, cases of VDPV and NPAFP can be tackled only by switching to IPV or Injectable Polio Vaccine.
India made the IPV a part of its routine immunization in November last year, but the detection of VDPV in Telangana suggests that more remains to be done to tackle the situation comprehensively.